* {
  margin: 0;
  padding: 0;
}
.big {
  width: 300px;
  height: 300px;
  position: absolute;
  top: 0;
  left: 360px;
  border: 1px solid #ccc;
  overflow: hidden;
  display: none;
}

.big img {
  position: absolute;
}
.small {
  width: 300px;
  height: 225px;
}
.mask {
  position: absolute;
  width: 100px;
  height: 100px;
  background-color: rgb(0, 0, 0);
  opacity: 0.3;
  display: none;
  pointer-events: none;
}
